Scandate cathode coated with Mo and Sc films

Sasaki, Shinji; Amano, Ikuma; Yaguchi, Toshie; Matsuzaki, N.; Yamada, E.; Taguchi, Sadanori; Shibata, M.

doi:10.1016/s0169-4332(96)00701-5

Cited by 10 publications

(4 citation statements)

References 3 publications

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“…Sc 2 O 3 has also been used for the stabilization of ZrO 2 thin films and as a dopant in nickel copper oxide based NO x sensors . The use of Sc 2 O 3 in cathodes in high-resolution and high-brightness cathode ray tubes has also been studied. , In this application Sc 2 O 3 together with W improves the cathode emission capability, although better emission characteristics have been obtained by metallic scandium overlayers . Furthermore, Sc 2 O 3 has attracted interest as a constituent of ferroelectric thin films, such as Pb[(Sc 0.5 Nb 0.5 ) 0.57 Ti 0.43 ]O 3 15 and Pb(Sc 0.5 Ta 0.5 )O 3 . , These materials have been studied for pyroelectric imaging and piezoelectric applications.…”

Section: Introductionmentioning

confidence: 99%

“…12,13 In this application Sc 2 O 3 together with W improves the cathode emission capability, although better emission characteristics have been obtained by metallic scandium overlayers. 14 Pb[(Sc 0.5 Nb 0.5 ) 0.57 Ti 0.43 ]O 3 15 and Pb(Sc 0.5 Ta 0.5 )O 3 . 16,17 These materials have been studied for pyroelectric imaging and piezoelectric applications.…”

Section: Introductionmentioning

confidence: 99%

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Surface-Controlled Deposition of Sc₂O₃ Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

Putkonen¹,

Nieminen²,

Niinistö³

et al. 2001

Chem. Mater.

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Scandium oxide thin film deposition by atomic layer epitaxy was studied at 175-500 °C using Sc(thd) 3 (thd ) 2,2,6,6-tetramethyl-3,5-heptanedione) and (C 5 H 5 ) 3 Sc as scandium precursors. A constant deposition rate of 0.125 Å (cycle) -1 was observed at 335-375 °C on Si(100) and soda lime glass substrates with Sc(thd) 3 and O 3 . The use of H 2 O 2 as an additional oxidizer slightly increased the deposition rate to 0.14 Å (cycle) -1 . When (C 5 H 5 ) 3 Sc and H 2 O were used as precursors, the growth rate of Sc 2 O 3 was significantly higher, viz., 0.75 Å (cycle) -1 at 250-350 °C. The effects of growth parameters such as reactant pulsing times were investigated in detail to confirm the surface-controlled growth mechanism. The crystallinity and surface morphology of the films were characterized by XRD and AFM, while ion-beam analysis (time-of-flight elastic recoil detection analysis) was used to determine the stoichiometry and impurity levels. Crystalline thin films with (111) as the dominant orientation were obtained on Si(100) when depositions were carried out at 300 °C or above from Sc(thd) 3 and O 3 precursors, while films deposited from (C 5 H 5 ) 3 Sc and H 2 O were polycrystalline regardless of the deposition temperature. When films were deposited at 300 °C onto Si(100), the preferred orientation changed from ( 111) to (100) when the film thickness exceeded 200 nm. Films were stoichiometric when deposited from Sc(thd) 3 /O 3 below 450 °C or from (C 5 H 5 ) 3 Sc/H 2 O at 250 °C or above. When the films were deposited from Sc(thd) 3 /O 3 , the carbon content was below 0.1 atom % regardless of the deposition temperature, whereas the hydrogen content decreased to below 0.1 atom % when the deposition temperature was increased to 375 °C. The C and H contents of the films, deposited from (C 5 H 5 ) 3 Sc/H 2 O at 300-400 °C, were around 0.1 and 0.5-0.3 atom %, respectively.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surface-Controlled Deposition of Sc₂O₃ Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

Putkonen¹,

Nieminen²,

Niinistö³

et al. 2001

Chem. Mater.

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“…and Sc 2 W 3 O 12 + 3Ba → 3BaWO 4 + 2Sc (17) This was proposed based on study of scandate cathodes with top-layer coatings consisting of W+Sc 2 O 3 [128] or W+Sc 2 W 3 O 12 [192], where it was concluded that only free Ba was available to react with the Sc-containing coatings as neither Al 2 O 3 nor CaO were detected at the cathode surface. Liu et al [139] studied the change in Sc concentration at cathode surfaces during activation and reported an increase over time for impregnated cathodes but not for unimpregnated cathodes.…”

Section: A Formation and Transport Mechanisms Of Free Metallic Ba And Scmentioning

confidence: 99%

“…In response to these demands for high current density emitters and novel electronic devices, Sc-containing "scandate" cathodes offering order-of-magnitude increases in emission current density and significant decreases in required operating temperatures have received a great deal of attention. Multiple investigations [10]- [17] have demonstrated the capabilities of scandate cathodes. Nevertheless, outstanding issues associated with both the reliable fabrication and operation of scandate cathodes-including non-uniform emission, low repeatability, and unpredictable longevity-continue to limit their application [10], [18]- [24].…”

Section: Introductionmentioning

confidence: 99%

A Review of Sc-containing "Scandate" Thermionic Cathodes

Seif¹,

Zhou²,

Liu³

et al. 2022

Preprint

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Although thermionic emission has been studied for more than 100 years, recent interest in novel electron devices for military and civilian use has led to a surge in demand for cathodes with enhanced emission properties (e.g. higher current density, more uniform emission, lower operating temperatures, or extended in-service longevity). Sc-containing "scandate" cathodes have been widely reported to exhibit superior emission properties compared to previous-generation thermionic cathodes, including oxide, B-, and M-type cathodes. Despite extensive study spanning several decades, the mechanism by which the addition of Sc enhances cathode emission remains ambiguous, and certain limitations -non-uniform emission, low reproducibility, inconsistent longevity -continue to prevent widespread commercial integration of scandate cathodes into electron devices. This review attempts to survey the literature to-date addressing the fabrication, structure, and properties of scandate cathodes, with particular attention to studies addressing the role of Sc in enhancing emission.

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Deducing surface chemistry and annealing conditions from observed nanoparticle shapes: A study of scandate cathodes

Seif

Balk

Beck

2022

Applied Surface Science

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Scandate cathode coated with Mo and Sc films

Cited by 10 publications

References 3 publications

Surface-Controlled Deposition of Sc₂O₃ Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

Surface-Controlled Deposition of Sc₂O₃ Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

A Review of Sc-containing "Scandate" Thermionic Cathodes

Deducing surface chemistry and annealing conditions from observed nanoparticle shapes: A study of scandate cathodes

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Scandate cathode coated with Mo and Sc films

Cited by 10 publications

References 3 publications

Surface-Controlled Deposition of Sc2O3 Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

Surface-Controlled Deposition of Sc2O3 Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

A Review of Sc-containing "Scandate" Thermionic Cathodes

Deducing surface chemistry and annealing conditions from observed nanoparticle shapes: A study of scandate cathodes

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Product

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Surface-Controlled Deposition of Sc₂O₃ Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

Surface-Controlled Deposition of Sc₂O₃ Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors